Bihar Chief Minister Nitish Kumar on Monday made an unscheduled visit to the national capital where he is likely to undergo medical treatment, besides, possibly, finalising seat-sharing arrangements with other NDA partners ahead of the 2019 Lok Sabha polls.

According to sources in the chief minister's office here, Kumar left for Delhi in the afternoon and is likely to stay there for the next couple of days.

The sources cited health reasons for Kumar's sudden visit to the national capital, which comes a day after the state executive meeting of his party -- Janata Dal (United).

However, senior party leaders, on condition of anonymity, said he could meet top BJP leaders to finalise a formula for seat-sharing in the Lok Sabha polls.

JD(U)'s Bihar unit president Vasishtha Narayan Singh had recently said a seat-sharing formula was likely to be arrived at "by mid-September".

At the JD(U)'s state executive meeting on Sunday, which saw the induction of poll strategist Prashant Kishor, Kumar reportedly told party workers that decks had been cleared for a "respectable" seat-sharing arrangement.

It is widely believed that among other things, Kishor is likely to be entrusted with the responsibility of ensuring proper communication between the JD(U) and other NDA partners, especially the BJP.